CAAnimationGroup 与 CAKeyframeAnimation 和 CABasicAnimation

Posted 2023-03-13

【中文标题】CAAnimationGroup 与 CAKeyframeAnimation 和 CABasicAnimation

【英文标题】：CAAnimationGroup with CAKeyframeAnimation and CABasicAnimation

【发布时间】：2013-07-31 23:06:14

【问题描述】：

我正在尝试沿曲线路径为视图设置动画并同时将其缩小：

CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    pathAnimation.calculationMode = kCAAnimationPaced;
    pathAnimation.fillMode = kCAFillModeForwards;
    pathAnimation.removedOnCompletion = NO;
    //Setting Endpoint of the animation
    CGPoint endPoint = endCenter;
    CGMutablePathRef curvedPath = CGPathCreateMutable();
    CGPathMoveToPoint(curvedPath, NULL, viewOrigin.x, viewOrigin.y);
    CGPathAddCurveToPoint(curvedPath, NULL, viewOrigin.x+200, viewOrigin.y-150, endPoint.x+100, endPoint.y+10, endPoint.x, endPoint.y);
    pathAnimation.path = curvedPath;
    CGPathRelease(curvedPath);

    // Set up scaling
    CABasicAnimation *resizeAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
    resizeAnimation.toValue = [NSNumber numberWithDouble:0.4];
    resizeAnimation.fillMode = kCAFillModeForwards;
    resizeAnimation.removedOnCompletion = NO;

    CAAnimationGroup *group = [CAAnimationGroup animation];
    group.fillMode = kCAFillModeForwards;
    group.removedOnCompletion = YES;
[group setAnimations:[NSArray arrayWithObjects: pathAnimation, resizeAnimation, nil]];
    group.duration = 3.7f;
    group.delegate = self;
    [group setValue:self.myView forKey:@"imageViewBeingAnimated"];

self.myView.center = endCenter;
self.myView.transform = self.myViewTransform;
[self.myView.layer addAnimation:group forKey:@"savingAnimation"];

问题在于，视图不是在移动时逐渐缩小，而是立即缩小，然后沿着路径移动。当它明显移动时，我需要按比例缩小。

【参考方案1】：

这样做解决了：

resizeAnimation.fromValue = [NSNumber numberWithDouble:1.0];

我不明白为什么我必须这样做。似乎应该从当前转换的默认 fromValue 开始。